1. Field of the Invention
The invention relates to a coaxial connector connected to a conductive panel, and more particularly, to a coaxial connector, a connecting part of which is to be connected to the conductive panel which is constituted of conductive material.
2. Related Art
A BNC connector is usually connected as a coaxial connector to be connected to a conductive panel.
In some BNC connectors, a signal ground of an external conductor is coupled directly to a ground frame of the conductive panel, to thereby ensure grounding. When a plurality of devices are interconnected by means of BNC connectors, such a grounding method enables formation of a ground loop by means of a potential difference among the devices. As a result, flow of an electric current arises among the devices.
In order to prevent formation of such a ground loop, there is described a capacitive-coupling connector, as disclosed in Japanese Patent No. 2578675.
In the capacitive-coupling connector, a capacitor is interposed between an external conductor and a conductive panel in order to connect them together. The capacitor enables electric discharge of electricity from the external conductor to the conductive panel so that the capacitive-coupling between the potential of the external conductor and the potential of the conductive panel may be made.
In the case of a BNC connector having a capacitor incorporated therein, a connection section (screws) must be constituted of an insulator so as to prevent direct connection between the external conductor and the conductive panel.
However, plastic is used as an insulative material for a connection section. Since plastic is a kind of dielectric material, an electromagnetic wave developed in the devices may radiate to the outside of the devices through a plastic member.
In this regard, when a coaxial cable is connected to a terminal on a conductive panel, a connection section of the connector is formed such that an external conductor of the connector, a plastic member (a dielectric substance), and a conductive panel are connected, in this order. Here, a plastic member (i.e., a dielectric substance) portion also serves as a screw. For this reason, the thickness of the plastic member (dielectric substance) portion cannot be made extremely thin. In order to connect the external conductor and the conductive panel to the connector while ensuring mutual isolation, a certain degree of thickness is required.
However, as the thickness of the plastic member (dielectric substance) increases, the distance between shield walls constituted of the external conductor and a conductive panel becomes greater, thereby failing to effectively shield an electromagnetic wave. Hence, a screw section of a conventional BNC connector having a certain thickness inevitably fails to prevent electromagnetic waves developed in a device from radiating to the outside of the device through the plastic member.
A clock frequency used in a device, which is mainly responsible for developing electromagnetic waves, is increasing year by year. Since the electromagnetic wave with a higher frequency can more easily pass through a dielectric substance due to the properties thereof, a leakage of the electromagnetic waves may become more.
In particular, a device having a plurality of connection ports radiates an electromagnetic wave to the outside of the device more as the number of ports is increased.
It is an object according to the present invention to provide a coaxial connector which lowers radiation of the electromagnetic wave to the outside of the device and is improved in electromagnetic compatibility (EMC). It is also an object to provide a manufacture method of thereof and a preventing method of electromagnetic wave leakage by using the coaxial connector.
According to the present invention, there may be provided a connector which has a connection part to be connected to a conductive panel made of a conductive material and a thin dielectric member formed for ensuring insulation between an external conductor and the conductive panel wherein the connector has a structure that the thin dielectric member (insulator), which may be a path of an electromagnetic wave, is sandwiched between the conductor and the conductive panel.
More specifically, the invention provides the followings.
(1) A coaxial connector having an elongated internal conductor, a cylindrical external conductor being coaxial with the internal conductor, and an insulation main body for fixing the internal conductor and the external conductor in an electrically-insulating manner,
wherein the insulation main body comprises a block part for fixing the internal conductor and the external conductor to a root part of the insulation main body with the internal conductor and the external conductor insulated from each other, and a cylindrical part for covering a portion of an outer periphery of the external conductor; and
wherein the cylindrical part of the insulation main body has a conductive member for shielding an electromagnetic wave.
According to the present invention, there is further provided a coaxial connector including:
an elongated internal conductor,
an external conductor, in which at least a portion of the internal conductor is inserted, and
an insulation main body fixing the external conductor and covering at least a portion of the external conductor;
the coaxial connector comprising:
a coaxial cylindrical dielectric member at least a portion of which is inserted between the internal and the external conductors;
wherein the insulation main body comprises a block part and a cylindrical part with both parts connected to each other substantially along the axis of the coaxial connector;
the block part securing the internal conductor and the cylindrical dielectric member via the external conductor;
the cylindrical part wrapping around and/or holding a portion of an outer periphery of the external conductor and being wrapped around and/or held on the outer periphery thereof by a conductive member so that the cylindrical part has such overlapping portion wrapping and being wrapped around.
According to the present invention, a conductive member for shielding (or blocking) passage of an electromagnetic wave is provided on an outer periphery of a cylindrical part of an insulation main body of a coaxial connector. And a connection portion of the coaxial connector has a structure having an external conductor, the cylindrical part (a dielectric member), and a conductive member connected in the order so that an electromagnetic wave (noise) that passes the dielectric member may be attenuated between shielding walls of the external conductor and the conductive member, thereby minimizing the leakage of a developed electromagnetic wave from the coaxial connector.
The conductive member, which may include a conductive flange as an example, also works as a screw which serves as a mount portion to a conductive panel. Since the screw is made of a conductive material such as metal, the strength of the screw is increased if compared to a plastic screw.
If it is needed to insulate the external conductor from the conductive panel, the cylindrical part should be made of insulating material because the cylindrical part is not insulated from the external conductor and because it serves as a mount portion to the conductive panel. However, the plastic screw may not have enough strength as a mounting portion. The thickness can be increased for the strength, but a thicker plastic mounting portion may cause leakage of an electromagnetic wave through the portion. Hence, a thinner plastic portion is more preferable.
According to the present invention, a cylindrical part (a dielectric member) is made thin and a mount part to a conductive panel is made of a conductive material. Although the cylindrical part (i.e., the insulation portion) is made thin, it secures the strength of the mount part by means of its mechanical property. The overlapping portion, for example, may include a portion having the cylindrical part (a dielectric member) wrapped around with an outmost cylindrical conductive flange and wrapping around the cylindrical external conductor. The cylindrical external conductor further wraps around the cylindrical dielectric member, which wraps around the coaxial internal conductor.
Here, with the coaxial connector, the internal conductor is generally an elongated thin conductor, which is assembled into the insulation main body so as to penetrate through the insulation main body. The external conductor, on the other hand, may be assembled into the insulation main body without penetrating the main body and stopped at a root part end face of the main body. The external conductor may be a long cylindrical conductor which encloses (or surrounds) the internal conductor and extends along the common axis of the internal conductor of the coaxial connector.
(2) The coaxial connector as recited in (1), comprising an electrical contact for constituting an electric circuit within the insulation main body;
wherein the electrical contact is inserted into an opening on a first side face of the block part such that it is connected to the external conductor and to the conductive member via a capacitor.
According to the present invention, as described above, the coaxial connector as recited in (1) comprises an electrical contact connected to the external conductor and the conductive member via a capacitor, wherein the electrical contact is inserted in an opening on a first side face of the block part.
According to the present invention, an electrical contact, which is conductive, may be inserted through an opening on a first side face of the block part and installed in a hollow space, which is connected to the opening, inside of the block part of the insulation main body. The electrical contact also may be connected to the conductive member and to the external conductor through a capacitor. The electrical contact contributes to an electric circuit within the insulation main body which may connect the coaxial connector to the ground so as to help the coaxial cable extending from the connector perform its functions.
With the conventional coaxial cable, an electrical contact for grounding the coaxial cable is provided in the vicinity of an mounting part of the connector and it is necessary for the electrical contact to contact with the conductive panel. The electrical contact is disposed inside the insulation main body, thereby enabling direct connection between the conductive panel and the conductive member, which is connected to the electrical contact via the capacitor. Hence, the reliability of the connection between the conductive panel and the conductive member can be enhanced.
If the electrical contact is provided outside the connector and has a spring finger which can elastically deform to engage with an electric element inserted into the connector, the connection between the electric element and the spring finger by pressing each other may have higher possibility to cause inadequate contact. According to the present invention, the electrical contact is installed within the connector and an unstable electrical contact between the electric element and the electrical contact can be prevented. Therefore, any disconnection in the electric elements may be prevented.
(3) The coaxial connector as recited in (1) or (2),
wherein the opening is disposed on the first side face and/or a second side face that opposes to the first side face; and
wherein the other two faces have no opening.
According to the present invention, the coaxial connector as recited in (1) or (2) is characterized in that the block part has four side faces and that the opening is disposed only on a first side face and/or a second side face opposing to the first side face.
(4) There is provided a coaxial connector having an insulation main body for fixing an internal conductor and an external conductor, which are electrically insulated from each other,
wherein the insulation main body has a block part for fixing the internal conductor and the external conductor at a root part; and a cylindrical section for covering a portion of an outer periphery of the external conductor;
wherein openings are disposed on a first side face and a second side face of the main body, which are opposing to each other; and
wherein no openings are disposed on other two faces opposing to each other.
According to the present invention, the insulation main body comprises four side faces surrounding the insulation main body,
wherein two openings formed on the side faces are disposed in two mutually-opposing side faces of the block part of the insulation main body of the coaxial connector; and
wherein no openings are disposed in the other two mutually-opposing side faces.
An opening making process and labor may be saved if compared to the conventional coaxial connector having openings in all side faces.
Since openings are disposed in only two mutually-opposing side faces of the block part, many coaxial connectors may be formed at the same time with molding dies which are aligned to the direction perpendicularly penetrating the other two side faces.
(5) There is also provided a device having a conductive panel to which the coaxial connector set forth in any one from (1) to (4) is attached.
According to the present invention, the coaxial connector set forth in any one of (1) to (4) may be attached to the conductive panel, thereby enabling communication between devices connected by way of the connector cable. So, advantages set forth in items (1) through (4) may be achieved. By way of example, such device may an include two-way and one-way communication devices.
(6) There is provided a method of manufacturing a coaxial connector having an insulation main body for fixing an internal conductor and an external conductor, which are electrically insulated from each other, wherein the insulation main body has a block part for fixing the internal conductor and the external conductor at a root part of the insulation main body, and a cylindrical part for covering a portion of an outer periphery of the external conductor, wherein the block part has an opening for inserting a predetermined part, the method comprising:
placing the insulation main body with the face of the opening in a predetermined direction, and
inserting the part through the opening.
According to the present invention, there is provided a method for making a coaxial connector having an insulation main body for fixing an internal conductor and an external conductor, which are electrically insulated from each other, wherein the insulation main body has a block part for fixing the internal conductor and the external conductor at a root part of the insulation main body, and a cylindrical part for covering a portion of an outer periphery of the external conductor, wherein the block part has openings for inserting predetermined parts on both or either of two opposing faces of the block part, the method comprising:
placing the insulation main body with the both or either of two opposing faces oriented as they face devices that provide the parts, and
providing the parts by pushing the parts.
According to the present invention, with the method for manufacturing the coaxial connector as recited in (3) or (4), a predetermined component (an electrical contact, a capacitor, and the like) may be placed in an opening leading toward the inside of the block part without turning the insulation main body.
In other words, in a method for making the coaxial connector recited in (3) or (4), openings (windows open at a side face or faces of the block part) are disposed on two mutually-opposing side faces of the block part and not in the remaining two mutually-opposing side surfaces of the same. It is possible that predetermined necessary components (or parts) are put together through holes (crevices, or openings to inside) in the two mutually-opposing faces of the block part without changing the direction of the faces. As a matter of course, there is no necessity for a process of putting a component into the other two surfaces which have no openings or windows.
According to the present invention, the number of processes and steps associated with the manufacture of the connector for the coaxial cable can be reduced.
(7) There is provided a method of lowering leakage of an electromagnetic wave from a coaxial connector, the connector having an insulation main body having a block part for fixedly positioning an internal conductor and an external conductor while they are electrically insulated from each other, and a cylindrical part for covering a portion of an outer periphery of the external conductor; the internal conductor being formed of an elongated conductor, the external conductor being coaxial with the internal conductor and being formed of a cylindrical conductor, wherein a conductive member to be attached to a conductive panel is provided on the outer periphery of the cylindrical part.
According to the present invention, there is provided a method of lowering leakage of an electromagnetic wave, comprising:
fixing on a conductive panel an coaxial connector having an insulation main body including a block part for fixedly positioning an internal conductor and an external conductor while they are electrically insulated from each other, and a cylindrical part for covering a portion of an outer periphery of the external conductor; the internal conductor being formed of an elongated conductor, the external conductor being coaxial with the internal conductor and being formed of a cylindrical conductor, wherein a conductive member to be attached to the conductive panel is provided on the outer periphery of the cylindrical part;
connecting the conductive member to the conductive panel; and
connecting a coaxial cable to the coaxial connector.
According to the present invention, a conductive material for shielding (or blocking) passage of an electromagnetic wave is provided on an outer periphery of a cylindrical part of the insulation main body. An electromagnetic wave (noise) is attenuated between the external conductor and the flange, thereby minimizing the dosage of an electromagnetic wave developing from the coaxial connector.
(8) The method for lowering leakage of an electromagnetic wave as recited in (7), wherein the cylindrical part of the insulation main body has even thinner.
According to the present invention, the cylindrical part of the insulation main body is made thinner so that the distance between the shield walls constituted of the external conductor and the conductive member becomes small. Hence, in most part between the shield walls, an electromagnetic wave travels uniformly and perpendicular to the walls, thereby enhancing the attenuation efficiency of the electromagnetic wave. Therefore, leakage of the electromagnetic wave from the coaxial connector can be suppressed further.